How are you controlling yours??

I see so many installations, with one of the most important part of the heat pump locked away in the cupboard under lock and key of the installer, why??

In these controls are advanced electronics and programming to let your heat pump achieve its full potential, so why not use these controls?

Instead I see lots of installs being controlled by “Smart Stats” i.e on/off stats that have the capability to link to your phone making it “smart”. These are what makes your heat pump cycle, These are what turn your heat pump on and off decreasing efficiency,These ironically are the least smart thing on the system.

Weather compensation alone is how your heating ideally should be running off. Whether it be Advanced weather compensation from Viessmann or Vaillant or even a basic weather compensation from Mitsubishi or Samsung. And if room influence is needed for compensating highly insulated rooms or rooms with solar gain the main controller should be used not third party unless used for limiting temperature only and have no direct link to the heat pump.

How this works? The first thing to understand is that weather compensation is a more gentle approach that’s proactive. It alters the radiator output before the house drops in temperature therefore not needing a higher temperature to ‘catch up’ with property heat loss.

With weather compensation you have an external temperature sensor. This Sensor is looking at your heat loss variable the Outside temperature, Your installer sets up your heat pump controller so that at design outdoor temperature (in our area is -3) The flow temperature of your heating circuit is at its highest ideally under 50-45 degrees maximum  Achieving the highest efficiency to achieve your desired room temperature. As the outdoor temperature increases your heat loss decreases so your heatpump would respond by lowering your flow temperature with doing so maintaining your desired indoor temperature without any drop in indoor temperature so maintaining that comfort you desire and lowering your energy bill in the process as you are only putting in just the correct amount of energy as you are losing though your building fabric.

What’s happening When you have on/off stats controlling your heat pump with weather compensation enabled also?? These work on internal temperature so what happens here is your outdoor temperature drops as doing so it lets your internal temperature drop and then sends a signal to your heat pump to start. Your heat pump will then look at the outdoor sensor and choose its flow Temperature based on the weather compensation curve thats been set up by your installer. The issue now is you have lost to much energy in your house so the return temperature is lower than your weather compensation curve so when the heat pump starts it needs to run at maximum Needing to “catch up” Just as your heat pump catches up and gets your house to temperature and wants to start modulating down for a greater efficiency your indoor stat hits the desired temperature and switches the heat pump off, this is Cycling and will continue throughout the day and night causing inefficiencies and high energy bills and should be avoided. With most installs with on/off stats are also not optimised and the weather compensation is set up to high to “catch up” quicker.

To achieve the highest Scop (efficiency) your heat pump must be running off its own controller and have limited interference from external stats, running of pure weather compensation to maintain a comfortable home at its highest efficiencies, this is what we talk about in the industry as low and slow, letting the heat pump run for long periods of time and its highest level of efficiencies mostly running at its lowest modulation using the as minimal electric as possible to produce the most heat output and maintaining your desired indoor temperature consistently throughout your house. There are always cases where indoor reference is needed mainly in houses with very high insulation levels and low heat demand or with high solar gain and there are ways of using the main controllers for indoor reference or having stats/trvs as limiting indoor temperature so your heat pump maintains good flow rates and long run times in rooms that still need it.

Controlling your Heat Pump